GUILLAUME FitzOsbern, son of OSBERN de Crépon & his wife Emma d'Ivry (-killed in battle Cassel, Flanders 22 Feb 1071, bur Abbaye de Corneilles[151]). Orderic Vitalis calls him nepos of Hugues Bishop of Bayeux[152]. Seigneur de Breteuil. "Willelmo filio Osberni et…Ælicia eius uxore filia Rogeri de Thoneio" founded the abbey of Lyre by charter dated 1046[153]. He founded the monastery of Corneilles in [1060] "on his own estates"[154]. "Willelmus et frater eius Osbernus" donated "terram…Herchembaldus vicecomes et Turoldus, comitissæ Gunnoris camerarius" and revenue from land received by "Croco et Erchembaldus filii eiusdem Erchembaldi vicecomitis" to the abbey of Sainte-Trinité at Rouen, with the consent of "matre eorum Emma", for the soul of "patris sui Osberni cognomento Pacifici", by charter dated to [1035/60], signed by "…Godeboldi, Daneboldi, Ansfredi filii Osberni, Gisleberti filii Turgisii…"[155]. "…Guillelmi filii Osberni…" witnessed the charter dated 1054 under which Guillaume II Duke of Normandy confirmed the donation of "terram…Sancta Columba…dedit Niellus clericus" to the abbey of Mont-Saint-Michel[156]. "…Guillelmus filius Osberti…Guillelmus filius Guillelmi filiii Osberti…" witnessed the charter dated to [1060] under which Guillaume II Duke of Normandy granted "Brenerias" to the abbey of Bayeux[157]. "Ansfredus, Osberni de Ou vicecomitis, postea…Hierosolimitani monachi, filius…cum conjuge mea Emma" offered "unicum filium meum…Goiffredum" as a monk at Sainte-Trinité de Rouen, with the consent of "dominis meis Emma, Osberni dapiferi uxore et filiis eius Willelmo et Osberno…Willelmo…principe Normannorum", by undated charter[158]. "Willelmus filius Osberti…" witnessed the charter dated 29 Aug 1060 under which "milite…Richardo…fratribus Willelmo…atque Balduino" donated "Gausberti Villa" to Chartres Saint-Père[159]. The Brevis Relatio de Origine Willelmi Conquestoris records that "Willelmo dapifero filio Osberni" contributed 60 ships towards the invasion of England in 1066[160]. The Chronique de Normandie, based on le Roman de Rou, records that William I King of England made "le Conte Rogier de Montgomery et Guillaume le filz Osber" his two "Marechaulx d´Engleterre" after the conquest of England[161]. "Erchenbaldo filio Erchenbaldi vicecomitis", on the point of leaving "ultra mare", donated property to Sainte-Trinité de Rouen, with the consent of "rege Anglorum et duce Normannorum Guillelmo", by undated charter, signed by "…Willelmi filii Osberni, Emmæ matris eius, Ansfredi filii Athlæ…"[162]. He fought at the battle of Hastings. William I King of England rewarded him for his part in the conquest of England with the grant of estates in the Isle of Wight and the county of Hereford, whereby he became Earl of Hereford. Florence of Worcester records that King William left "fratrumque suum Odonem Baiocensem episcopum et Willelmum filium Osberni quem in Herefordensi provincia comitum" when he went to Normandy 21 Feb [1067][163]. "Willelmus comes filius Osberni dapiferi" donated rights in "totius silvæ Longum Bothel" to Sainte-Trinité de Rouen by charter dated 1068, which states that later "Willelmus…filius eius" confirmed the donation[164]. Florence of Worcester records that "Willelmi Herefordensis comitis" seized treasure from monasteries in England 17 Feb [1070][165]. King William I appointed him regent of Normandy in [1071][166]. The Chronicon Lyrensi records that "Willelmus filius Osberni" was killed by "Roberto Frison die Dominica Septuagesimæ" in 1072 and buried "Apud Cormelias"[167]. He was killed supporting the accession of Arnoul III Count of Flanders, whose mother he had married as his second wife, against Robert I "le Frison" Count of Flanders. Robert of Torigny's De Immutatione Ordinis Monachorum records that "Willermus filius Osberni Normanniæ dapifer et cognatus Willermi ducis" was buried "apud Cormelias"[168]. The necrology of the monastery of Ouche records the death "20 Feb" of "Willelmus Britolii comes"[169]. The necrology of Lyre monastery records the death "20 Feb" of "Guillelmus comes institutor hujus loci"[170].
m firstly (before 1046) ADELISA de Tosny, daughter of ROGER de Tosny & his wife Godechildis --- (-6 Oct ----, bur Abbaye de Lire). Guillaume de Jumièges names "Adelise fille de Roger du Ternois" as wife of "Guillaume fils d'Osbern, proche parent du duc Guillaume", recording that her husband buried her in the monastery of Lire which he had built[171]. "Willelmo filio Osberni et…Ælicia eius uxore filia Rogeri de Thoneio" founded the abbey of Lyre by charter dated 1046[172]. Robert of Torigny's De Immutatione Ordinis Monachorum records that "Willermus filius Osberni Normanniæ dapifer et cognatus Willermi ducis…Aelizam uxorem suam filiam Rogeri de Toeneio" was buried in the monastery of Lire[173]. The necrology of Lyre monastery records the death "6 Oct" of "Adeliz uxor Willelmi hujus loci fundatoris"[174]. The necrology of the monastery of Ouche records the death "6 Oct" of "mater Willelmi Britolii Adeliza"[175].
m secondly (after Jul 1070) as her third husband, RICHILDE, widow firstly of HERMAN Comte de Hainaut and secondly of BAUDOUIN VI Count of Flanders, daughter of --- (-Messines 15 Mar 1087, bur Hanson Abbey). The question of the possible parentage of Richilde is discussed fully in the document HAINAUT, dealing with her first husband's family. The Annals of Winchester record the marriage in 1070 of "comitissam Flandriæ" and "rex…nepoti suo Willelmo filio Osberni"[176]. William of Malmesbury records that Baudouin I comte de Hainaut entrusted the guardianship of his two sons to "Philip king of France…and to William Fitz-Osberne", adding that the latter "readily undertook the office that he might increase his dignity by a union with Richilda"[177]. The Complete Peerage, citing "Annales Flandriæ", states that Richilde was taken in battle where her new husband FitzOsbern was killed[178], but the precise reference has not yet been found to this primary source. The necrology of Liège Saint-Lambert records the death "XVII Kal Apr" of "Richildis comitisse"[179].
Earl Guillaume & his first wife had four children